Click on CURRENT to see the current trending (Health Check).
Click on HISTORY to see the historical evolution of the trending.

Quality Control within the VLT data flow is mainly performed on calibration products. The main purpose is to monitor and asses the technical performance of the instrument and the atmospheric properties. E.g. a user defines a constraint of 1.0'' seeing. The executed OB is checked at the observatory immediately and the OB gets a QC grade within the QC0 process, meaning the constraint set is checked. The result of the QC0 process is a statement like: The seeing equals or is better than the constraint. When the science spectra are processed the average PSF of the spectrum can be derived from the science product. The QC1 parameter (in this case the QC1 parameter is dependent on the actual atmospheric seeing and instrumental parameters like the filter wavelength and the performance of the optical alignment like focus). The QC1 process although applied to science products still measures instrumental and atmospheric properties. It also measures properties of the sources (like source fluxes or intensities), but is does not measure how far the science products are suitable to perform the intended science goal of the underlying observing proposal.

- system offset between skylines derived from the associated telluric standard star product and the sky lines derived from the science spectrum. Both QC.WLEN values are subtracted and converted in pixel. Values are of reliable if both wavelength calibrations are derived from the sky lines with qc_xcorr > 0.5.